In this paper, we describe the musical development of a new system for performing electronic music where a video-based eye movement recording system, known as Oculog, is used to control sound. Its development is discussed against a background that includes a brief history of biologically based interfaces for performing music, together with a survey of various recording systems currently in use for monitoring eye movement in clinical applications. Oculog is discussed with specific reference to its implementation as a performance interface for electronic music. A new work features algorithms driven by eye movement response and allows the user to interact with audio synthesis and introduces new possibilities for microtonal performance. Discussion reflects an earlier technological paradigm and concludes by reviewing possibilities for future development.